In a mobile phone network such as LTE (Long Term Evolution) and the like, in order to reduce an operation cost of the network, there is used an SON (Self Organizing Network) technique for autonomously optimizing various types of wireless-parameters. In this technique, in general, the need for optimizing the network is determined by using measurement results in a UE (User Equipment) that is a communication terminal and an eNB (evolved Node B) that is a wireless base station and information of a peripheral eNB acquired via an X2 interface. When it is determined that the optimization is necessary, an optimum wireless-parameter value for the network is determined using the aforementioned information, and the wireless parameter value is changed to a determined value.
In the method disclosed in PTL 1, for example, an optimum transmission power of a pico BS (Base Station) is determined by using an RSRP (Reference Signal Received Power) value measured in a pico UE, and a transmission power of a pico eNB is changed. At that time, even when another pico eNB exists in a neighborhood, the transmission power of the pico eNB is optimized without considering a state of optimization execution of the pico eNB existing in the neighborhood.
Further, PTL 2, for example, discloses a system in which state control information in a wireless base station is reported to an adjacent wireless base station via a control station, and wireless parameters are efficiently set to appropriate values.